Exemplary embodiments of the inventive concepts relate to methods for manufacturing a single crystalline silicon layer capable of being transferred to and used in another substrate on which it is difficult to deposit silicon at a high temperature. More specifically, the exemplary embodiments of the inventive concepts relate to methods for manufacturing a single crystalline silicon layer capable of being easily transferred to another substrate, such as a flexible substrate, by removing an intermediate oxide layer of an SOI substrate using light irradiation and an etchant.
With research and development of technologies and materials for manufacturing high-performance electronic devices, recent research has focused on flexible devices. As representative flexible devices, organic devices using organic materials may be advantageously fabricated on various substrates such as a plastic substrate because their fabrication temperatures are low. However, there remains a lack of understanding and researching regarding the materials. Therefore, a number of researches and efforts are required for practical technology commercialization. Besides these researches, many efforts are being made to fabricate flexible devices using silicon whose performance and theory are already established.
Since the deposition temperature for a silicon layer is very high (approximately 1,400 degrees centigrade), it is not possible to directly apply the silicon layer to a flexible substrate such as plastic having poor heat resistance. In order to overcome this problem, there is proposed a method including depositing a silicon layer at a conventional high temperature, separating only the silicon layer element, and bonding the separated silicon layer element onto a flexible substrate. One of the conventional methods is that after a single crystalline silicon layer is deposited on a substrate, holes are formed at the single crystalline silicon layer at regular intervals to remove an intermediate oxide layer or make the deposited single crystalline silicon layer in the form of thin ribbon.
However, a single crystalline silicon layer is easily damaged when a hole is formed at the single crystalline silicon layer or the single crystalline silicon layer is patterned in the form of ribbon. Therefore, these methods are not suitable to obtain a intact single crystalline silicon layer. Moreover, since a large-area single crystalline silicon layer capable of being easily transferable to another substrate cannot be obtained even by the above conventional method, there is a limitation in practical fabrication of devices.